The International Standard Organization (ISO) is a recognized authority for industry standards. ISO-14229 specifies data link requirements of diagnostic services allowing a diagnostic tester or test equipment to control diagnostic functions in a vehicle electronic control unit (ECU); e.g., ECUs associated with electronic fuel injection, automated gear box assemblies, anti-lock braking systems, etc. When the diagnostic test equipment interfaces with one or more ECUs, the test equipment controls communication over the data link—e.g., whether the communication is to stop, pause, or resume.